poj 3278 Catch That Cow

#include<iostream>
#include<queue>
using namespace std;
#define MAXSIZE 100001
int main()
{
int N,K,tmp,step,a[MAXSIZE];
while(scanf("%d%d",&N,&K)!=EOF)
{
memset(a, -1, sizeof(a));
queue<int> q;
q.push(N);
a
=0;
//bfs
while(!q.empty())
{
step=q.front();
q.pop();
tmp=step-1;
if(tmp>=0 && a[tmp]==-1)
{
a[tmp]=a[step]+1;
q.push(tmp);
if(tmp==K)
break;
}

tmp=step+1;
if(tmp<MAXSIZE && a[tmp]==-1)
{
a[tmp]=a[step]+1;
q.push(tmp);
if(tmp==K)
break;
}

tmp=step<<1;
if(tmp<MAXSIZE && a[tmp]==-1)
{
a[tmp]=a[step]+1;
q.push(tmp);
if(tmp==K)
break;
}
}
printf("%d/n",a[K]);
}
return 0;
}